Leukocyte and platelet lowering by some interferon types during viral hepatitis treatment

BACKGROUND/AIMS: The hematologic toxicity (leukothrombocytopenia) of interferon therapy is well known and frequently observed; it may vary, however, according to the type of interferon administered. METHODOLOGY: We retrospectively assessed 158 patients with chronic viral hepatitis treated for 6-12 months with alpha (recombinant, lymphoblastoid or leukocyte) or beta interferon to monitor leukothrombocytopenia. RESULTS: During treatment, a significant decrease in leukocyte and platelet counts was detected in 48% and 43% of patients, respectively. The maximum decrease (31% and 26% of pre-treatment values; p <0.01) occurred after 4.9 and 4.2 months of treatment. No patient showed clinical symptoms of leukopenia or thrombocytopenia. Beta-interferon yielded the smallest decreases in leukocyte and platelet counts (-21% and -16% of pre-treatment values, respectively). Among alpha interferons, the lymphoblastoid (9 MU/week) produced the largest decrease both in leukocyte (38%; p <0.05 vs any other type) and in platelet (32%) number. The same dose of leukocyte interferon had the smallest effect (leukocytes: -27%; platelets: -2%), while recombinant interferon showed intermediate toxicity (-32% and -26% respectively). CONCLUSIONS: From this retrospective study, the hematologic toxicity of α and α interferons usually emerges as mild. However, leukopenia and thrombocytopenia may be induced more frequently by some of these interferon types.